1. Field of the Invention
The present invention relates to an image forming apparatus.
2. Description of the Related Art
There is known an image forming apparatus which scans the circumference face of a photosensitive drum, the circumference face being charged, with laser light to form electrostatic latent images on the circumference face thereof, and develops the electrostatic latent images with a developing agent to form toner images on the circumference face thereof. It is also known that in such an image forming apparatus, a partition wall is disposed between the photosensitive drum and a scanning optical device which scans the photosensitive drum with the laser light so that the scanning optical device is prevented from being stained with toner or the like adhering to the photosensitive drum. However, in order to ensure a space to dispose the partition wall, a gap between the photosensitive drum and the scanning optical device becomes large, and accordingly a space to dispose the photosensitive drum and the scanning optical device becomes large, whereby the image forming apparatus becomes large. Then, as disclosed in Japanese Patent Application Laid-Open Publication No. hei 8-15935 or as shown in FIG. 12 of the present application, there is known an image forming apparatus in which a part of a scanning optical device projects to a side where a photosensitive drum 102 is disposed from a partition wall 103 so that a space to dispose the photosensitive drum 102 and the scanning optical device is made small.
However, as shown in FIG. 12, which shows the same case as the image forming apparatus disposed in Japanese Patent Application Laid-Open Publication No. hei 8-15935, an emergence unit 101, from which laser light emerges so that the photosensitive drum 102 is irradiated with the laser light, abuts the partition wall 103. Hence, vibration generated by operation of components of the image forming apparatus is propagated to the emergence unit 101 through the partition wall 103, and causes shifts (deviates) rays of the laser light, which emerges from the emergence unit 101. That is, accuracy of emergence of laser light from the scanning optical device is decreased, and the decrease of the accuracy of emergence of laser light results in poor image formation, such as deterioration of image quality.